Finds the root cause of a bug, test failure, or unexpected behavior before proposing any fix. Use this whenever something is broken and the cause is not yet proven — a failing test, a production error, intermittent behavior, or a symptom that appeared after a change. Also use when a fix has been attempted and did not work, or when the same bug keeps coming back.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Systematic debugging
## The rule
**No fix before the cause is proven.** A change that makes a symptom disappear without an
explanation has not fixed anything — it has moved the failure somewhere you are not looking.
## Method
1. **Reproduce it deterministically.** If you cannot make it happen on demand, you cannot know when
it is fixed. Intermittent means you have not found the variable yet — order, timing, state,
environment, data.
2. **Narrow the blast radius.** Bisect: which commit, which input, which branch, which layer. Halve
the search space with each step rather than reading everything.
3. **State a hypothesis that can be wrong.** "The cache returns stale rows after a write" is a
hypothesis. "Something is wrong with caching" is not.
4. **Test the hypothesis directly** — a log line, a breakpoint, a probe. Prove it, do not infer it.
5. **Explain the whole symptom.** If your cause explains the error but not why it started Tuesday,
you have found *a* bug, not *the* bug.
6. **Fix, then verify by reverting.** Put the bug back and confirm the test fails again. This is the
step people skip, and it is the one that proves causation rather than coincidence.
…
The line at the top of this page pins the label git:20260901.aa45383, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
A 17 of 17 checks passed. Fixed automatic checks with no AI involved, so the same checks give the same answer every run.
pass: Frontmatter block present
pass: Frontmatter declares a name
pass: Frontmatter declares a description
pass: Size between 200 bytes and 200 KB (2642 bytes)
pass: No zero-width or bidi control characters
pass: No instruction hidden inside an HTML comment
pass: No link to an exfiltration or paste host
pass: No credential-shaped string
pass: No instruction to send local credentials anywhere
pass: No text hidden with inline styles
pass: No prompt-injection phrasing
pass: No curl or wget piped into a shell
pass: No recursive delete of root, home or parent
pass: No instruction to read or print local credentials
pass: No base64 blob over 200 characters
pass: No link to a raw IP address
pass: No script tag
Source
GitHub
cbrock84/headcount · 2,076 stars · license MIT · pushed 2026-10-18 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_xxzgeicqbmwsxr77
GET https://markdownregistry.com/api/v1/resolve?ref=cbrock84/headcount/systematic-debugging
GET https://markdownregistry.com/api/v1/blob/9fb2d3075ed42bbcb500a30ea5c451a9acb186fc2359b2f8531d9a24f4f913c2
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
cbrock84/headcount · plugins/corporate-strategy/skills/chief-strategy-officer/SKILL.md · Owns where the business plays and how it wins over a multi-year horizon — portfolio choices, corporate development…
cbrock84/headcount · plugins/corporate-strategy/skills/market-entry/SKILL.md · Decides whether and how to enter a new market — sizing demand from the bottom up rather than from a market report…
cbrock84/headcount · plugins/corporate-strategy/skills/portfolio-strategy/SKILL.md · Decides where capital and attention go across business lines, products, and markets — what to fund, hold, harvest, or…
cbrock84/headcount · plugins/corporate-strategy/skills/scenario-planning/SKILL.md · Plans under genuine uncertainty — building scenarios, identifying which assumptions are load-bearing, setting…
cbrock84/headcount · plugins/corporate-strategy/skills/strategic-alliances/SKILL.md · Structures partnerships that change what the business can do — technology integrations, channel and reseller…
cbrock84/headcount · plugins/customer-experience/skills/chief-customer-officer/SKILL.md · Owns the customer's experience after the sale — support, success, escalation, and the feedback loop back into product…
cbrock84/headcount · plugins/customer-experience/skills/customer-onboarding-and-implementation/SKILL.md · Takes a new customer from signature to working — setting a definition of live that both sides agreed before the…
cbrock84/headcount · plugins/customer-experience/skills/customer-success-management/SKILL.md · Runs the ongoing relationship with accounts after the sale — segmenting coverage against account value, building a…
cbrock84/headcount · plugins/customer-experience/skills/escalation-management/SKILL.md · Handles customer situations that have exceeded normal support — severity assessment, incident communication, executive…
cbrock84/headcount · plugins/customer-experience/skills/self-service-and-knowledge/SKILL.md · Builds the help center, in-product guidance, and knowledge base that let customers resolve problems without contacting…
mvschwarz/openrig · skills/_canonical/process/systematic-debugging/SKILL.md · Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes
mvschwarz/openrig · packages/daemon/specs/agents/shared/skills/process/systematic-debugging/SKILL.md · Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes
a5c-ai/babysitter · library/methodologies/superpowers/skills/systematic-debugging/SKILL.md · Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes. Requires root cause…
